Latch



Feb. 18, 1941. E. w. NORTH ETAL LATCH Filed May 5, 1959 lvl/Tl/l/g fda;Milian 0. 5am/ie 12/ W/Orfl/ INVENTORS Patented eb. 18, 1941 'UNITEDSTATES PATENT OFI-lcs LATCH Edwin W. North and 0. Burke, Rockford, Ill.,assignors to National Lock Co., Rockford, Ill., a corporation ofDelaware Application May 5,1939, Serial No. 271,853

4 Claims.

'I'his invention relates to improvements in latches, one of theprincipal objects being the provision of intermediate lever and linkingmechanism providing an operative connection between the operating handleand the latch bolt in a latch of the slam-shut variety such as isco'mmonly employed on refrigerators and the like.

A further object is the provision ofA improvements in the mounting andoperative connection or association of an operating plunger with thelatch handle and an intermediate lever mechanism for operating the bolt.

A further object is the provision of improved handle means in which ahandle and mounting therefor Vconstitutes a. unit with an operatingplunger associated as a part of the unit and A of construction as wellas the arrangement and operation of the parts in the illustrativeembodiment described hereinafter in viewvof the annexed drawing, inwhich:

Fig. 1 is a horizontal section through a latch structure. and operatinghandle mounted on a refrigerator door;

Fig. 2 is a vertical section along line 2-2 of Fig. 1;

Fig. 3 is a vertical section along line 3 3 of Fig. 1 through the latchbolt;

Fig. 4 is a rear perspective of the latch with portions of the mountingframe cut away;

Fig. 5 is a fragmentary rear perspective of the4 handle unit. i

Latches of the slam-shut variety, that is to say, whichI employspring-urged bolts normally disposed in latching position for cammingengagement with a keeper when .the door is slammed shut, are subject toa great deal of mechanical stressdue to the impact of the bolt with thekeeper, and in order to make an economical latch from1 the standpoint ofproduction cost, a yproblemarises in providing an operating leverage ormechanism which is simple, inexpensive, of high mechanical advantage,and withal rugged and freey from reasonable likelihood -of mechanicalbreakdown due to abuse or wear. Such latches are commonly employed withrefrigerators and other utility devices of this class,`and thearrangement is commonly such that the operating handle for the latch isimpositively associated with the latch-operating mechanism; that is tosay, the latch' bolt and associated operating means is movableindependently of the handle so that the door may be slammed shut withoutmoving the handle.

' It is practically possible to manufacture a latch of this class whichwill be adequately rugged and free from mechanical trouble, but theproblems arise in constructing such a latch along economical lines forproduction purposes. The

present invention provides an operating mechanism which is sim-ple andinexpensive and overcomes the diiiiculties heretofore experienced inconstructing this type of latch.

In its preferred embodiment, the new latch consists of a mountingbracket l5 (Figs. 2, 3 and 4) formed by bending a heavy metal strap backupon itself to provide a channel having a bottom portion I6 and oppositeside walls I1. At one end, the strap. has upset flanges I8 for mountingpurposes. Near an opposite end of the channel there is an inturnedtongue I9 (Figs. 1 and 2) embossed toprovide a seat for one end of acoil spring 20. The opposite end of this spring engages a knobular seaton the inner end of a latch bolt 2| which slides in the channel -part ofthe bracket against the inner surface of the bottom Wall I6 and sidewalls I1. A roller 2 2 is mountedon a pin 2,3, seated in the oppositeside walls Il, in spaced relation to the bottom of the channel i6 so asto guide the bolt in its reciprocable movement into and out of latchedposition, that is, in a direction into and out of the channel part ofthe bracket. The spring 20 normally urges the bolt into latched positionas seen in Fig. 1, and the bolt is provided with a cammed nose portion24 which is engageable with a keeper 25 and which, upon striking thelatter, coacts with the eammed surface of the keeper to force the bolttoward unlatched position for movement into the latching part of thekeeper by reaction of the spring 20 when the door or other closure isclosed.

The bolt is provided with an operating mechanism which includes a. vpairof parallel straps 26 (Fig. 4 particularly) riveted thereto as at 21 andextending inwardly into the channel on opposite sides of the spring 20.The rearward or inner end portions of each of these straps are providedwith elongated slots 28 through which extends a ystationary guide pin 29secured in the opposite wall portions I1 of the mounting bracket. Thus,the bolt proper is guided at its forward end 'between the bottom wall I6of the channel part of the bracket and the roller22, and at its rear thebolt structure is guided by the pin 29.

An intermediate operating lever 30 is pivotally mounted on a pin 3|between opposite wall portions I'I of the bracket, and this lever is ofpeculiar shape and formed by bending a piece of metal back upon itselfso that there will be spaced opposite side walls joined b y anintermediate wall portion 32 (Figs. 1, 2 and 4). This latterintermediate wall portion is curved inwardly and is disposed at one sideof the pivot 3| for engagement with the operating plunger 33 of a handleunit. The inner end of this plunger works in the inwardly or concavelycurved part of the intermediate wall portion 32 when a handle member 50is suitably rocked, and as a result, the intermediate lever is pivotedso as to displace the far end portion 35 toward the right in the`general direction of retractive movement of the bolt. This intermediateoperating lever may preferably be of the construction described andclaimed in our copending application, Serial No. 271,854, iiled May 5,1939.

Means for providing a connection of great mechanical advantage andsimplicity includes a link strap 36 having opposite end portions turnedback upon itself to provide eyes 31 and 38, the

former of which pivotally engages a pin 39 bend straightening out oreven loosening.

mounted in the opposite wall portions of the lever 30 near the end 35thereof, and the latter eye 38 pivotally engaging a pin 40 mountedbetween projections 4I on the parallel straps 26.

The pivotal connections between the bolt structure and the intermediateoperating lever 30 through the agency of the link 36 are such that whenthe lever 38 is displaced toward the right (Fig. 1), by inward movementof the plunger 33, the movement of the link means 35 will be almostrectilinear in the direction of movement of the bolt. Effort of thespring 20 restores the bolt, the operating mechanism and the plunger tothe normal position shown in Fig. 1.

It will be apparent that the bolt and its associated operating mechanism30-38 is capable of movement independently of the plunger 33. The lever30 may be conveniently and inexpensively constructed as a simplestamping which is additionally strengthenedby the provision of the pinmeans 39 connecting it with the link, and the link 36 may likewise bemanufactured as a simple stamping.

The nearly rectilinear movement of the link 36 with respect to the lineof reciprocation of the bolt, brings an appreciable part of the load onthe eye portions 31 and 38 very close to the initial bends at the endsof the link and which constitute the eye portions, so that unusuallyheavy stock need -not be employed in anticipation of the possibility ofthe bight or eye portions of the In addition, the momentary shock whichthe eye portions of the link 36 must withstand at the time of impact ofthe bolt with the keeper, is adequately withstood as a result of theconstruction and arrangement of the link as aforesaid.

A further consideration of importance is the fact that fby arranging thepivots of the inter-` almost in a straight line parallel with the move-lment of the bolt so that the pull on the bolt is largely in a straightline therewith and thereis no wasted torque or turning effort as aresult of excessive pivotal movement which would cause the pivotal'centers to shift relative to each other during retraction of the bolt.For example, in Fig. 1 the pivot 39 is closer to the axis of the boltthan pivot 49 and lies at one side of a. line through pivot 40 andnearer to the bolt than pivot Ill. This arrangement ,not only reduceswear on the parts. but takes maximum advantage of the leverages involvedin a manner such that the effort applied to the handle may be moreuniform throughout the retractive movement of the bolt and not, as inthe case of some older latches, easy at first but increasingly resistantuntil the bolt is nally fully withdrawn. To the same end, the pivot ofthe link on the intermediate lever and the pivotal axis of the latterlie along'a line making a small angle with the length of the plunger.These small angles are as small as possible for any similar dispositionoi' parts with respect to relative location and dimension, and whichywill also prevent the pivoting members from getting into dead centers"and thus jamming.

Another feature of importance is the construction of the handlemechanism as a unit, as illustrated particularly in Figs. 2 and 5,wherein the handle member 50 is a hollow formed-up stamping which rockson a pintle 5i mounted on opposite side wall flanges 52 of achannel-shaped mounting bracket, a bottom portion 53 of which is adaptedto t against the door. A plate 54 is welded or otherwise secured tosmall upset flanges 55 (Fig. 4) on the latch bracket and fits againstthe inside oi' the door face opposite the handle part 58. Means such asthe screws 56 passing through holes 51 punched in the bottom of thehandle bracket, are employed to attach the handle bracket to the plate54.

The handle is provided with the usual spring.

58 for maintaining the same in a normal position. In the arrangementillustrated, the handle is mounted in an upside-down position comparedwith the conventional mounting, so that the handle must be pulled downaway from the door structure upon which it is mounted.

A bearing plate 59, moving with the handle, is provided near the openend portion at one side of the pintle 5I so as to bear against the head60 of the operating plunger 33. 'I'he plunger is slidable in a bushing5| seated in the bottom portion 53 oi' the handle mounting bracket.Thus, the handle structure is an independent unit which may beassociated with a latch structure such as shown in Fig. 1, or with someother type of lock adapted to coact with the plunger 33 and adapted tohave the bracket portion 53 mounted therewith so that the plunger willbe disposed in operative position relative vto the latch mechanism.

The specic recitation of certain details of construction and operationof the preferred embodiment hereinbefore described is not to beconstrued as a limitation upon the invention except to the extent thatmay be provided in the appended claims.

Having thus described our invention, what we claim as new and desire toprotect by Letters Patent is: Y

1. In a latch of the type adapted to be actuated by a reciprocableplunger, a plunger and handle structure comprising a mounting plate, ahandle pivoted on said plate to rock about an axis parallel with theplane of the plate, a bushf ter and actuate ing seated in the plate atone side of the rocking axis oi.' the handle, a plunger reciprocable insaid a bearing surface, and'stop means preventing the plunger fromworking out handle having a hollow of the bushing, said portion oppositethe headed end of the plunger,l a bearing elementmounted in said hollowportion to rock coaxially with said handle and having a surface portiondisposed to bear againstl the headed part of the plunger and anotherportion bearing against an eccentric part oi' the handle whereby rockingof the handle toward the plunger will move the latthe latch, and springmeans interposed between said mounting plate and said bearing elementand urging the latter against the handle, whereby the handle and bearingelement are moved into a normal position in a direction away from theplunger.

2. In a latch oi' the otype includinga rocking handle adapted to engagea latch-operating plunger to move the latter in a direction normally ofthe rocking axis of the handle, the combination of: a plunger, a handlestructure including a mounting, a handle on said mounting to rock towardthe latte a bushing in the mounting disposed at a point eccentric of therocking axis of the handle, a plunger in said bushing, said handlehaving a hollow end portion opposite an end of said plunger, a bearingelement mounted torock coaxially with the handle in the hollow portionthereof and having a part engaged by the handle when the latter isrocked toward the plunger and a part engaging theend of the plunger whenthe handle is rocked as aforesaid to constitute a slidable bearingconneclfign between the handle and plunger, andspring means interposedbetween said mounting and bearing element to urge able with said plungerand l formed up to provide a handle portion with an enlarged open endportion, a mounting member, and means including a pintle extendedthrough said enlarged open end portion mounting the vharidlefor rockingmovement away from said mouting member, and a thrust element in the formof a plate member with offsets constituting mounting-ears which aremeans at said open end said thrust element may rock independently of thehandle but coaxially therewith, said thrust element having athrust-receiving portion offset from said pintle' means and disposed toengage a marginal portion of said open end of the handle for movement bythe latter in a direction toward said mounting member, spring meansinterposed between said mounting member and thrust element, normallyurging the latter against said end portion of the handle to dispose thelatter in a normal position, said thrust-receiving portion of theelement being adapted to engage the end of a latch operating plunger formovement in a direction transversely of said pintle means. v`

4. In combination with a pivoted latch operating handle having a hollowend portion and adapted to move a reciprocable plunger opposite said endportion, a thrust-receiving element pivoted coaxially with said handlein said hollow end portion and having a surface part engagea partengaged by said handle, whereby movement of the latter toward saidplunger will cause said thrustreceiving part to bear against the plungerfor the purpose set forth.

EDWIN W. NORTH.

O. BURKE.

of the handle whereby engaged with said pintle

